JPH0579496A - Impeller of blower - Google Patents

Abstract

PURPOSE:To suppress the rapid increase of the noise through prevention of reverse flow in the vicinity of a boss part and to increase a static pressure by devising the shape of each blade formed in a three-dimensional shape, in the axial flow impeller of a blower used for a ventilating fan or the like. CONSTITUTION:In a three-blade-shaped impeller, each impeller 1 is attached to a boss part 2 in a state to be formed in a three-dimensional shape. In which case, a chord line central point PR in a section available when a rotary shaft 3 is cut by a cylindrical surface with a radius R centering around a rotary axis 3 and a radius R0 being 35% of an impeller chip radius Rt are set as a virtual boss part 2. When a distance between the chord line central point R and a plane Sc passing a chord line central point P0 in a section when the rotary shaft is cut by a cylindrical surface with an impeller chip radius R0 and crossing the rotary shaft 3 at right angles is LS, the value of a forward inclination angle deltaz represented by a formula of deltaz= tan<-1> (Ls/(R-R0)) is set to a range of 12.5-32.5 deg.. Further, an inclination angle alpha of a boss part is set in a range from 15 to 35 deg. and an angle deltatheta of lead in the rotation direction of the tip part of the impeller in a range from 25 to 40 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial flow impeller used for a ventilation fan, an air conditioner and the like, and more particularly to an impeller of a blower capable of reducing the aerodynamic noise to the limit.

[0002]

Blowers are widely used in air conditioners, ventilation fans and the like, and it is very important socially to reduce the noise generated from the impeller as much as possible. Among the conventional techniques, Japanese Patent Publication No. 2-2
As disclosed in Japanese Patent Publication No. 000, this was done by clarifying the parameters that determine the three-dimensional shape of the impeller and optimizing the shape. FIG. 14 is a perspective view showing an impeller of a conventional blower disclosed in Japanese Patent Publication No. 2000-2000. In the figure, 1 is the blade of the impeller, 1a is the tip of the blade,
1b is a blade front edge portion, 1c is a blade trailing edge portion, 1d is a blade outer peripheral portion, 2 is a boss portion for attaching the blade, 3 is a rotation axis, and 4 is a rotation direction. Further, FIG. 15 is a projection view when the impeller is projected on a plane orthogonal to the rotation axis 3, 1'is a blade in the plan view, 1a 'is a blade tip portion in the plan view, and 1b' is a plane projection. The blade leading edge portion 1c ′ in the drawing is the blade trailing edge portion in the plan view, and 1d ′ is the blade outer peripheral portion in the plan view. Further, FIG. 16 shows that from the boss chord line center point Pb ′ in FIG.
For t -Synthesis of Pt 'trajectory PB'-P _R in the radial direction to the '', chord line center point chord line center point P _R rotates projected radius R in the plane OX surface at an arbitrary radius R P _R Shows the radial distribution of and the cross section of the blade 1 at the same position. In FIG. 17, when the blade surface is formed with the blade chord line center point P _R as a relative origin, the blade 1 is cut by a cylindrical surface having a radius R and the cross section is developed into a two-dimensional plane. In the figure, 5 is a warp line, 5a is a blade negative pressure surface, 5b is a blade pressure surface, and 6 is a rotation axis parallel line. In this impeller, the three-dimensional curved surface shape of the blade 1 is specifically defined by clarifying various factors constituting the blade 1.

In the projection plane when the impeller is projected on the plane orthogonal to the rotation axis in FIG. 15, the blade chord line center point in the cross section when the boss portion of the blade is cut by the cylindrical surface of radius Rb is Rb '. And the rotation axis as the origin O,
The point O and Rb 'a straight line connecting the points in a coordinate system whose X-axis, a chord line center points when cutting the blade in the cylindrical surface of radius R P _R' as a linear Rb'-O When the angle formed by the X axis is δθ (δθ: forward angle in the rotation direction), δ
The radial distribution of θ is δθ = δθt × (R−Rb) / (R
t-Rb) (Rt: blade tip radius, Rb: blade boss radius, δθt: angle formed by straight line P _R ′ -O and the X axis), and δθt = 40 ° to 50 °, and in FIG. The chord line center point P _R in the cross section when the impeller is cut along the cylindrical surface having the radius R centering on the rotation axis, and the chord line in the cross section when the boss portion of the blade is cut along the cylindrical surface with the radius Rb. A plane S passing through the center point Pb and orthogonal to the rotation axis
When the distance from c is Ls, the chord line center point P _R is always positioned in the positive direction with respect to the Sc plane in a coordinate system in which the suction side of the air flow is in the positive direction, and δz = tan ⁻¹ ( L
s / (R-Rb)) (δz: suction direction forward tilt angle) has a value of δz of δz = 12.5 ° to 32.5 °, and in FIG. 17, the blade is cut along a cylindrical surface having a radius R. Then, in the development view obtained by developing the cross section into a two-dimensional plane, the shape of the warp line in the blade cross section is an arc shape, and the central angle for forming the arc shape is θ (θ: warp angle). In this case, the radial distribution of θ is θ = (θt−θ
₀ ) × (R−R ₀ ) / (Rt−R ₀ ) / θ ₀ (θt: deflection angle at blade tip, θb: deflection angle at blade boss portion), θt = 20 ° to 30 °, θb = 27 ° to 37 °,
θt <θb, and the blade mounting position is the chord line 1
If the angle formed by b-1c and the straight line 6 that is parallel to the rotation axis 3 and that passes through the blade leading edge portion 1b is the skew angle ξ, the radial distribution of ξ is ξ = (ξt−ξb) × (R− Rb) /
(Rt−R ₀ ) + ξb (ξt: angle of the blade tip, ξb: angle of the blade boss)
t = 62 ° to 72 °, ξb = 53 ° to 63 °, ξt> ξ
b, and L in FIG. 17 is the chord length, and the blade size is limited by the chord chord ratio T / L using the circumferential distance T between the blades shown in FIG. T / L = 1 to 1.1 at each radius point. By using such an impeller having a three-dimensional curved surface, the development of the boundary layer on the impeller surface is suppressed and the state of the discharge vortex is changed. Therefore, the impeller of a blower having a considerably low noise over a wide operating region to some extent. It was.

[0004]

Although the impeller of the conventional blower has the characteristics of low noise as described above, as shown in FIG. 19, in the vicinity of the operating point where the air volume is reduced to some extent and wind pressure is applied. In addition, a backflow 11 from the blow-out side to the suction side has occurred near the boss 2, and there is a problem that noise increases sharply. At the operating point where the flow in the radial direction becomes stronger in this way, the conventional axial flow impeller greatly advanced in the rotational direction has a substantially shorter chord length along the flow,
Further, since the substantial warp angle becomes small, it is difficult to increase the static pressure above a certain level.

The present invention has been made in order to solve the above-mentioned problems, and suppresses a sudden increase in noise by eliminating backflow in the vicinity of the boss portion, and achieves high static pressure and high performance. The purpose is to obtain a low-noise fan impeller.

[0006]

[Means for Solving the Problems] Claim 1 according to the present invention
The impeller of the blower of FIG. ₃ has an imaginary blade chord line center point P _R and a radius R ₀ of 35% of the blade tip radius Rt in the cross section when the impeller is cut along a cylindrical surface having a radius R centering on the rotation axis. Is set as a typical boss portion, and the distance from the plane Sc passing through the chord line center point P ₀ and orthogonal to the above-mentioned rotation axis in the cross section cut by the cylindrical surface having the radius R ₀ is Ls,
In the coordinate system in which the suction side of the air flow is in the positive direction, the chord line center point P _R is always positioned in the positive direction with respect to the Sc plane, and δz = tan ⁻¹ (Ls / (R−R ₀ )) ( δz: The value of δz that can be expressed by the suction direction forward tilt angle is δz = 12.5
And 32.5 °, and the actual boss portion has a circular truncated cone shape that is smaller toward the suction side, and the value of the rotation axis direction inclination angle α is α = 15 ° to 35 °, and In the projection plane when the impeller is projected on a plane orthogonal to each other, the chord line center point in the cross section when the virtual boss portion of the blade is cut by the cylindrical surface of the radius R ₀ is P ₀ ′, and the rotation axis is With the origin O as the origin O, and a line connecting the above point O and the point P ₀ 'with X
In the coordinate system with the axis, a straight line P _R ′ -O where P _R ′ is the center point of the chord line when the blade is cut along a cylindrical surface with a radius R
The angle between the X axis and the above is δθ (δθ: forward angle of rotation)
, The radial distribution of δθ is δθ = δθt ×
Given by (R−R ₀ ) / (Rt−R ₀ ), δθt = 25 °
It is set to -40 °.

According to a second aspect of the present invention, the impeller of the blower has a blade chord line center point P _R and a blade tip radius in a cross section when the impeller is cut along a cylindrical surface having a radius R centering on the rotation axis. set the radius R ₀ 35% of Rt as a virtual boss, a plane Sc perpendicular to chord line center point P ₀ in the cross-section of a cutaway of a cylindrical surface of the radius R ₀ and as the rotating shaft And the distance Ls is Ls, the chord line center point P _R is always positioned in the positive direction with respect to the Sc plane in a coordinate system in which the suction side of the air flow is the positive direction, and δz = tan
^-1 (Ls / (R-R ₀ )) (δz: suction direction forward tilt angle), the value of δz is δz = 12.5 ° to 32.5 °, and the actual boss is closer to the suction side. A small circular truncated cone is used, and the value of the tilt angle α in the rotation axis direction is α = 15 ° to 3
On the projection plane when the impeller is projected on a plane that is 5 ° and is orthogonal to the rotation axis, the center of the chord line in the cross section when the virtual boss portion of the blade is cut by the cylindrical surface of radius R ₀ Let the point be P ₀ 'and the rotation axis be the origin O,
In the coordinate system where the straight line connecting the O point and the P ₀ point is the X axis,
When the blade is cut along a cylindrical surface having a radius R, the center point of the chord line is P _R ′, and the angle between the straight line P _R ′ -O and the X axis is δθ (δθ: forward direction angle of rotation). In this case, the radial distribution of δθ is δθ = δθt × (R−R ₀ ) / (Rt−
R ₀ ), δθt = 25 ° to 40 °, and the blade is cut along a cylindrical surface with a radius R, and its cross section is developed into a two-dimensional plane. Is a circular arc shape, and the central angle for forming the circular arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt−θ ₀ ) × (R−R ₀ ). / (Rt
−R ₀ ) + θ ₀ (θt: Deflection angle at blade tip, θ ₀ :
R ₀ = 0.35 Rt) and θt = 2
5 ° to 35 °, θ ₀ = 32 ° to 42 °, and θt <θ _0, and in the above developed view, the chord line of the blade and the straight line parallel to the rotation axis and passing through the leading edge portion of the blade. The angle ξ
(Ξ: angle of deviation), the radial distribution of ξ is ξ = (ξt−ξ ₀ ) × (R−R ₀ ) / (Rt−R
₀ ) + ξ ₀ (ξt: Angle of rake at blade tip, ξ
₀ : R ₀ = 0.35 Rt), ξt = 58 ° to 68 °, ξ ₀ = 49 ° to 59 °, ξt
When t> ξ _0, and in the above developed view, the chord length of the blade is L and the pitch at the same radial point between the blades is T, the ratio T / L (T /
L: node ratio) T / L = 1.3 to 2.0.

[0008]

The impeller of the blower according to the present invention clarifies the three-dimensional distribution of the blade element center, which is the skeleton for determining the blade shape. Especially, the blade blade element center is inclined to the gas suction side, is advancing in the rotation direction, and the boss is inclined, and each distribution is optimized, so high static pressure and It has achieved low noise at the same time.

[0009]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of an impeller of a blower according to the present invention, which has, for example, a three-blade shape. Regarding the description of the operation, one blade 1 will be mainly described, but other blades will be described. Is also the same. In the figure, 1 is a blade of an impeller having a three-dimensional shape, 2 is a boss portion for mounting the blade, 3 is a rotation axis of the blade 1, and 4 is a rotation direction. The characteristic of the blade 1 is that the blade surface is twisted spatially, and moreover, the blade surface is greatly inclined forward toward the gas suction side.
It has a dimensional curved surface shape, the second boss portion has an inclination angle in the rotation axis direction, and has a circular truncated cone shape that is smaller on the suction side. In this impeller, by clarifying various factors constituting the blade 1, the blade 1
The three-dimensional curved surface shape can be concretely defined. Then, concretely, the factors constituting the impeller according to the present invention will be shown. FIG. 2 is a projection view when the blade 1 is projected on a plane orthogonal to the rotation axis 3, 1'is a blade on the projection surface, 2 is a boss portion, 3 is a rotation axis, and the radius R is from the rotation axis 3. 'arc 1b _R in the projection plane obtained by cutting the' blade 1 in the cylindrical surface of the -P _R '-1c _R' is a blade cross-sectional shape. Here, P _R 'is an arc 1b _R ' -1c _R '
Is the midpoint of the chord line on the projection plane. In order to clarify the position of P _R 'on the projection plane, apart from the actual boss portion of the truncated cone shape, the blade tip radius Rt of 35
%, A virtual boss portion having a radius of P ₀ is set, and it is assumed that the blades also exist up to this virtual boss portion for convenience, and the impeller is cut at the cylindrical surface of the virtual boss portion having a radius R ₀ . When the boss chord line center point P ₀ ′ on the projection plane at that time is set, and the straight line P ₀ ′ −O connecting the rotation axis 3 to the position O on the projection plane is set as the X axis, and the coordinates with O as the origin are on the projection surface. To form.
Pt 'is the chord line center points in the outer peripheral portion 1d, Pθ' is the chord line center point P 'chord line center points in the trajectory P _{0' R} -P _R '
The angle between the tangent line of -Pt 'and the radius R is shown. Further, the reference numeral with a dash (') indicates each part on the projection surface. In the above coordinate system, if the angle between the straight line P _R '-O and the X axis is δθ (δθ: forward direction angle in the rotation direction) and the distance is R, the position of P _R ′ is (R, δθ). It can be expressed in a polar coordinate system. In the present invention, the straight lines Pt'-O and X
If the angle formed by the axis is δθt, δθ = δθt × (R−
R ₀ ) / (Rt−R ₀ ), and δθt = 25 ° -40
It is supposed to be °. In this way, the position of the chord line center point Pb can be defined on the plane orthogonal to the rotation axis 3, so the axial position is defined next.

FIG. 3 shows a radial locus P ₀ '-P _R ' -Pt 'from the virtual boss chord line center point P ₀ ' to the outer peripheral chord line center point Pt 'in FIG. , A radius R of the chord line center point P _R at an arbitrary radius R on the plane OX plane
2 shows the radial distribution of the chord line center point P _R which is rotationally projected at, and the cross section of the blade 1 at the same position. In the figure, 7 indicates centrifugal force when the impeller is rotated, 7a and 7b indicate negative pressure surface normal component of the centrifugal force 7, tangential component, and arrow A indicates the gas inflow direction. Therefore, consider a plane Sc that passes through the chord line center point P ₀ of the blade 1 in the outer peripheral portion of the virtual boss portion and is orthogonal to the rotation axis 3. When the chord line center point at an arbitrary radius R is P _R , the plane Sc and the chord line center point P _R
Is Ls, and the virtual boss part chord line center points P ₀ and Sc
If the angle made by the plane is δz, δz = tan ⁻¹ (Ls
/ (R-R ₀ )) (δz: suction direction forward tilt angle), and the value of δz is set to δz = 12.5 ° to 32.5 °. Further, the actual boss portion 2 has an angle of α with respect to the rotation axis, and has a circular truncated cone shape that is smaller on the suction side, and the value of α is set to α = 15 ° to 35 °.

In FIG. 4, when the blade surface is formed with the chord line center point PR as a relative origin, the blade 1 is cut by a cylindrical surface having a radius R and its cross section is developed into a two-dimensional plane. The developed view is shown. The blade warp line 5 has an arc shape, a warp angle that is a central angle for forming the arc is θ, and a radius forming the arc is RR. In this embodiment, the radial distribution of θ is θ = (θt−θ ₀ ) × (R−R ₀ ) / (R
t−R ₀ ) + θ ₀ , where θt is the deflection angle at the blade tip, that is, the central angle of the deflection line at the blade tip, and θ ₀ is the deflection angle at R ₀ = 0.35Rt, that is, the virtual boss of the blade. Given by the central angle of the warp line in the section, θt = 25 ° ~
35 °, θ ₀ = 32 ° to 42 °, and θt <θ ₀ . Also, the mounting position of the blade is the chord line 1b-1c,
The angle formed by a straight line 6 which is parallel to the rotation axis 3 and which passes through the blade leading edge portion 1b is determined as a stagger angle ξ, and ξ has a radial distribution. That is, the radial distribution of ξ is ξ = (ξt−ξ ₀ ) × (R−R ₀ ) / (Rt−R ₀ ) +
ξ ₀ , where ξt is the angle of the blade tip
ξ ₀ is given as a stagger angle at the virtual boss portion of R ₀ = 0.35Rt, ξt = 58 ° to 68 °, ξ ₀ = 49 °
˜59 °, ξt> ξ ₀ . Further, L in this figure is the chord length, and the value of the chord chord ratio T / L defined by the ratio with T which is the circumferential distance (pitch) between the blades shown in FIG. T / L = 1.3-
It is set to 2.0.

As described above, by setting the six parameters to unique values, an extremely low noise and high static pressure impeller can be obtained. An example in which the values of these parameters are all optimized will be shown below as an example, and the effect on the noise characteristics when the value of each parameter is changed will be described as a result of experimental examination. R ₀ = 0.35 Rt α = 25 ° δz = 22.5 ° (constant in the radial direction) δθ = 30 ° × (R−R ₀ ) / (Rt−R ₀ ) θ = −7.5 ° × (R _{-R 0) / (Rt-R} 0) +37
° ξ = 9 ° × (R−R ₀ ) / (Rt−R ₀ ) + 54 ° T / L = 1.6 (constant in the radial direction) Backflow near the boss shown in FIG. 19 as a problem of the conventional example. No. 11 is improved by making the shape of the boss portion into a circular truncated cone shape that is smaller toward the suction side, and the noise level can be significantly reduced. However, if the boss inclination angle α is made too large, the blowout dynamic pressure (value in which the energy of the blowout speed is converted into pressure) loss increases due to the decrease in the blowout area, and the performance deteriorates. Therefore, there is an optimum range of the boss inclination angle α. Fig. 6 shows the result of an experimental examination of the effect of α on the noise characteristics. Here, the comparative noise level Ks (phone) is a value defined by the following equation. Ks = SPL-10Log ₁₀ (Q × Ps ^2.5 ) SPL: Noise level (phone) Q: Flow rate Ps: Static pressure As can be seen from this equation, Ks means the noise level per unit flow rate / static pressure, Same aerodynamic specifications (flow rate
Under the static pressure condition, it can be said that the smaller Ks is, the lower the noise of the impeller is. Since the specific noise level Ks also changes depending on the operating point, the value at the operating point where Ks is the minimum is graphed in FIG. As can be seen from FIG. 6, if the boss inclination angle α is between 15 ° and 35 °, the value of the minimum specific noise level Ks is sufficiently small and the noise is extremely low.

The effect of the forward inclination of the blade 1 toward the suction side is basically the same as that of the conventional example, and the negative pressure surface normal component force 7a of the centrifugal force 7 in FIG. The layers can be made thinner and the noise generated is reduced. As can be seen from FIG. 7, the optimum range of the suction direction forward inclination angle δz is δz = 12.5 ° to 32.5 ° as in the conventional example, but the noise deterioration when deviating from this range is larger than that in the conventional example. A remarkable tendency can be seen. The optimum range of the rotation-direction forward angle δθ was significantly different from that of the conventional example. In the impeller of the present invention in which the radial direction flow is strengthened by providing the boss inclination angle α, the blade which is advanced considerably in the rotation direction with a large δθ follows the actual streamline 8 as shown in FIG. As a result, the substantial chord length 9 became shorter, the shape suitable for increasing the wind pressure tended to go backward, and the aerodynamic performance deteriorated, resulting in an increase in the minimum specific noise level Ks. After all, the optimum range of δθ is, as is clear from FIG. 9, the advancing angle δ at the blade tip.
δθt = 25 ° to 40 ° with respect to θt. Due to the above shape changes, the minimum specific noise level K compared to the conventional example
s (phone) was reduced by about 3 phones.

Example 2. Subsequently, influences of the blade shape parameters other than the above, such as the warp angle θ, the stagger angle ξ, and the chord chord ratio T / L will be described. Generally, the larger the warp angle θ and the smaller the swivel angle ξ are, the more aerodynamic performance is improved. In the impeller of the present invention in which the radial flow is strengthened as compared with the conventional example, the substantial warp angle considered from the actual streamline is small, and the deviation angle is large, so the optimum range is expected to change from the conventional example. Was done. As a result of experimentally examining these, as shown in FIGS. 10 and 11, θt = 25 ° to 35 ° θ ₀ = 32 ° to 42 ° and ξt = 58 ° to 68 ° ξ ₀ = 49 ° to 59 ° The range became clear. These values are values in which the warp angle θ is increased by 5 ° and the swivel angle ξ is decreased by 4 ° as compared with the conventional example. Also, the optimum range of the chord chord ratio T / L was T / L = 1.0 to 1.1 in the conventional example, but since the static pressure increase due to the centrifugal force effect of the radial flow also becomes large, the blade chord length L Even if is shortened to a certain extent (T / L is increased), the aerodynamic performance is not significantly deteriorated, and the noise reduction effect due to the shortened chord length is greater, so the minimum specific noise level Ks is reduced. From the experimental result of FIG. 11, the chord ratio T /
It became clear that the optimum range of L is T / L = 1.3 to 2.0. By changing the above three types of shape parameters, it was possible to further reduce the noise of the two phones.

Example 3. In the above embodiment, the number of blades is 3
Although the number of blades is described, if the essential parameters are configured as described above, the same effect can be expected regardless of the number of blades.

Example 4. Further, when the impeller according to the present invention is manufactured by die molding using a material such as plastic, the notch 10 is formed in the boss 2 as shown in FIG. -No impact on noise characteristics.

Embodiment 5. Looking at this invention from the aspect of strength,
Since the radius near the boss portion at the trailing edge of the blade, which is the most problematic, is large due to the inclination of the boss portion, the strength is increased as compared with the conventional example. Further, in the embodiment, the case where the boss suction side radii Rb are the same as R ₀ (= 0.35Rt) is shown, but even if Rb> R ₀ is set to further secure the strength, a relatively similar effect is obtained. Can be expected.

[0018]

The present invention has the following effects.
In the impeller of the blower according to claim 1, the blade chord line center point P _R in the cross section when the impeller is cut along a cylindrical surface having a radius R centering on the rotation axis and a radius R of 35% of the blade tip radius Rt.
₀ is set as a virtual boss portion, and a distance from a plane Sc passing through the blade chord line center point P ₀ and orthogonal to the rotation axis in a cross section when cut by the cylindrical surface having the radius R ₀ is defined as Ls. At this time, in the coordinate system in which the suction side of the air flow is in the positive direction, the chord line center point P _R is always positioned in the positive direction with respect to the Sc plane, and δz = tan ⁻¹ (Ls / (R−R ₀ ). )
The value of δz that can be expressed by (δz: forward tilt angle of the suction direction) is δz
= 12.5 ° to 32.5 °, and the actual boss portion has a circular truncated cone shape that is smaller toward the suction side, and the value of the rotation axis direction inclination angle α is α = 15 ° to 35 °, and In the projection plane when the impeller is projected on the plane orthogonal to the rotation axis, the blade chord line center point in the cross section when the virtual boss portion of the blade is cut by the cylindrical surface of radius R ₀ is P ₀ ′. ,
In the coordinate system with the rotation axis as the origin O and the straight line connecting the point O and the point P ₀ ′ as the X axis, the center point of the chord line P _R when the blade is cut by the cylindrical surface with the radius R is P _R. If the angle between the straight line P _R '-O and the X axis is δθ (δθ: forward angle in the rotation direction), the radial distribution of δθ is δθ =
δθt × (R−R ₀ ) / (Rt−R ₀ ), and δθt
= 25 ° to 40 °, the forward inclination angle δz in the suction direction, the boss inclination angle α, and the advance angle δθ in the rotation direction, which are essential parameters that define the spatial distribution of the blade chord line center point P _R.
Since the impeller of the blower is configured by optimizing the above, the backflow in the vicinity of the boss part is eliminated to suppress the rapid increase of noise, and
Although it has a large air volume and low noise over a wide effective operation area, it has an effect of obtaining an impeller of a blower that has high performance and can significantly reduce noise particularly in a high static pressure area.

According to another aspect of the fan impeller of the present invention, the blade chord line center point P _R and the impeller tip radius Rt are 3 in the cross section when the impeller is cut along a cylindrical surface having a radius R centering on the rotation axis.
A radius R _{0 of} 5% is set as a virtual boss portion, and a plane Sc passing through the chord line center point P ₀ in the cross section when cut along a cylindrical surface having this radius R ₀ and orthogonal to the rotation axis When the distance is Ls, the chord line center point P _R is always positioned in the positive direction with respect to the Sc plane in a coordinate system in which the suction side of the air flow is in the positive direction, and δz = tan ⁻¹ (Ls / ( R
−R ₀ )) (δz: suction direction forward tilt angle)
Is set to δz = 12.5 ° to 32.5 °, and the actual boss portion is formed into a circular truncated cone with a smaller circle on the suction side, and the value of the rotation axis direction inclination angle α is α = 15 ° to 35 °. And the virtual boss portion of the blade has a radius R _{0 on} the projection plane when the impeller is projected on a plane orthogonal to the rotation axis.
P ₀ 'is the center point of the chord line in the cross section when cut along the cylindrical surface of P, and the rotation axis is the origin O.
_In the coordinate system with the straight line connecting the ₀ 'point as the X axis, the center point of the chord line when cutting the above blade with a cylindrical surface of radius R is P _R '
Is the angle between the straight line P _R '-O and the X axis is δθ.
(Δθ: forward angle of rotation), the radial distribution of δθ is δθ = δθt × (R−R ₀ ) / (Rt−R ₀ ).
And δθt = 25 ° to 40 °, and the blade is cut by a cylindrical surface having a radius R and the cross-section is developed into a two-dimensional plane. In the case of an arc shape and the central angle for forming the arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt−θ ₀ ) × (R−R ₀ ) / (Rt -R
₀ ) + θ ₀ (θt: Deflection angle at blade tip, θ ₀ : R ₀
= Warp angle at 0.35 Rt), θt = 25 °
˜35 °, θ ₀ = 32 ° to 42 °, θt <θ _0, and in the above developed view, the angle formed by the chord line of the blade and the straight line parallel to the rotation axis and passing through the leading edge portion of the blade. Ξ (ξ:
The angle distribution of ξ is ξ =
(Ξt−ξ ₀ ) × (R−R ₀ ) / (Rt−R ₀ ) + ξ ₀
(Ξt: wing angle at blade tip, ξ ₀ : R ₀ =
The angle of deviation at 0.35Rt), ξt = 5
When 8 ° to 68 °, ξ ₀ = 49 ° to 59 °, ξt> ξ _0, and in the above developed view, the chord length of the blade is L, and the pitch at the same radius point of the blade is T. ,
Ratio of T and L at each radius point T / L (T / L: chord ratio)
Is T / L = 1.3 to 2.0, and the blade chord line center point P
The forward inclination angle δz in the suction direction, the boss inclination angle α, and the advance angle δ in the rotation direction, which are essential parameters that define the spatial distribution of _R.
θ, warp angle θ, swivel angle ξ, and chord ratio T / L are optimized to constitute an impeller of a blower, which suppresses a backflow near the boss portion and suppresses a sudden increase in noise.
Although it has a large air volume and low noise over a wide effective operating region, it has an effect of obtaining an impeller of a blower which has high performance and can significantly reduce noise particularly in a high static pressure region.

[Brief description of drawings]

FIG. 1 is a perspective view showing an impeller of a blower according to an embodiment of the present invention.

FIG. 2 is a projection diagram when the blades are projected on a plane orthogonal to the rotation axis of the impeller of the blower according to the embodiment of the present invention.

3 is a radial locus P ₀ 'from the boss chord line center point P ₀ ' in FIG. 2 to the outer peripheral chord line center point Pt '.
For -P _R '-Synthesis of Pt', radial distribution of chord line center point P _R rotated projected radius R of chord line center point P _R at an arbitrary radius R in the plane OX surface, and at the same position of the blade It is sectional drawing which shows the cross section of.

FIG. 4 is a cross-sectional view of an impeller of a blower according to an embodiment of the present invention. When a blade surface is formed with a blade chord line center point P _R as a relative origin, the blade is cut by a cylindrical surface having a radius R, and It is a development view obtained by developing a cross section into a two-dimensional plane.

FIG. 5 is a plan view showing an impeller of a blower according to an embodiment of the present invention.

FIG. 6 is a graph showing changes in the minimum specific noise level Ks (phone) with respect to the boss inclination angle α in the impeller of the blower according to the embodiment of the present invention.

FIG. 7 is a graph showing changes in the minimum specific noise level Ks (phone) with respect to the suction direction forward tilt angle δz of the impeller of the blower according to the embodiment of the present invention.

FIG. 8 is a diagram showing actual streamlines on a plane of an impeller.

FIG. 9 is a graph showing changes in the minimum specific noise level Ks (phone) with respect to the advancing angle δθt at the blade tip in the impeller of the blower according to the embodiment of the present invention.

FIG. 10 is a graph showing changes in the minimum specific noise level Ks (phone) with respect to the deflection angle θt at the blade tip in the impeller of the blower according to the embodiment of the present invention.

FIG. 11 is a graph showing changes in the minimum specific noise level Ks (phone) with respect to the stagger angle ξt at the blade tips in the impeller of the blower according to the embodiment of the present invention.

FIG. 12 is a diagram showing an impeller of a blower according to an embodiment of the present invention, in which a minimum specific noise level Ks with respect to a stringing ratio T / L
It is a graph which shows the change of (phone).

FIG. 13 is a perspective view showing a notched boss in the impeller of the blower according to the embodiment of the present invention.

FIG. 14 is a perspective view showing an impeller of a conventional blower.

FIG. 15 is a diagram corresponding to FIG. 2 in a conventional impeller of a blower.

FIG. 16 is a diagram corresponding to FIG. 3 in a conventional impeller of a blower.

FIG. 17 is a view corresponding to FIG. 4 in a conventional impeller of a blower.

FIG. 18 is a plan view of a conventional impeller of a blower.

FIG. 19 is a side sectional view showing a flow in an impeller of a conventional blower.

[Explanation of symbols]

 1 Blade 1'Blade in Plan View 1a Blade Tip 1a 'Blade Tip in Plan View 1b Blade Leading Edge 1b' Blade Leading Edge 1c in Plan View 1c Blade Trailing Edge 1c 'Blade Rear in Plan View Edge portion 1d Blade outer peripheral portion 2 Boss portion 3 Rotation axis 4 Rotation direction 5 Sled line 5a Blade negative pressure surface 5b Blade pressure surface 6 Rotation axis parallel line 7 Centrifugal force 7a Centrifugal negative pressure surface normal direction component 7b Centrifugal force negative Pressure surface tangential component 8 Streamline 9 Chord length 10 Boss notch 11 Backflow of boss

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhisa Otatsu 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Corporation Central Research Laboratory (72) Inventor Taro Sekimoto 8-1-1 Tsukaguchihonmachi, Amagasaki Mitsubishi Central Research Laboratory of Electric Co., Ltd. (72) Inventor Kimoto Wada 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Engineering Co., Ltd. Itami Works

Claims (2)

[Claims] 1. A chord line center point P _R in a cross section when the impeller is cut along a cylindrical surface having a radius R centering on the rotation axis.
And a radius R ₀ of 35% of the blade tip radius Rt is set as an imaginary boss portion and passes through the chord line center point P ₀ in the cross section when cut along the cylindrical surface of this radius R ₀ When the distance to the orthogonal plane Sc is Ls, the chord line center point PR is always positioned in the positive direction with respect to the Sc plane in a coordinate system in which the suction side of the airflow is the positive direction.
The value of δz that can be expressed by δz = tan ⁻¹ (Ls / (R−R ₀ )) (δz: forward tilt angle of the suction direction) is δz = 12.5 ° to
32.5 °, and the actual boss has a circular truncated cone shape with a smaller diameter on the suction side, and the value of inclination angle α of the rotation axis direction is α = 15 ° to 35 °
And the virtual boss portion of the blade has a radius R on the projection plane when the impeller is projected on a plane orthogonal to the rotation axis.
_In a coordinate system in which the center point of the chord line in the cross section when cut by the cylindrical surface of ₀ is P ₀ ′, the rotation axis is the origin O, and the straight line connecting the point O and P ₀ ′ is the X axis. , P is the center point of the chord line when the above blade is cut along a cylindrical surface of radius R
'As, linear P _{R' R} the angle of -O and the X-axis δ
When θ (δθ: forward angle of rotation), the radial distribution of δθ is δθ = δθt × (R−R ₀ ) / (Rt−R
₀ ), and δθt = 25 ° to 40 °, an impeller of a blower. 2. A chord line center point P _R in a cross section when the impeller is cut along a cylindrical surface having a radius R centering on the rotation axis.
And a radius R _0, which is 35% of the blade tip radius Rt, is set as a virtual boss portion, and passes through the chord line center point P ₀ in the cross section when cut by the cylindrical surface of this radius R ₀ , and the above-mentioned rotation axis Let Ls be the distance to the plane Sc that is orthogonal to the plane Sc in the coordinate system with the suction side of the airflow in the positive direction, the chord line center point P _R is always located in the positive direction with respect to the Sc plane,
The value of δz that can be expressed by δz = tan ⁻¹ (Ls / (R−R ₀ )) (δz: forward tilt angle of the suction direction) is δz = 12.5 ° to
32.5 °, and the actual boss has a circular truncated cone shape with a smaller diameter on the suction side, and the value of inclination angle α of the rotation axis direction is α = 15 ° to 35 °
And the virtual boss portion of the blade has a radius R on the projection plane when the impeller is projected on a plane orthogonal to the rotation axis.
_In a coordinate system in which the center point of the chord line in the cross section when cut by the cylindrical surface of ₀ is P ₀ ′, the rotation axis is the origin O, and the straight line connecting the point O and P ₀ ′ is the X axis. , P is the center point of the chord line when the above blade is cut along a cylindrical surface of radius R
'As, linear P _{R' R} the angle of -O and the X-axis δ
When θ (δθ: forward angle of rotation), the radial distribution of δθ is δθ = δθt × (R−R ₀ ) / (Rt−R
₀ ), δθt = 25 ° to 40 °, and the blade is cut by a cylindrical surface having a radius R, and its cross section is developed into a two-dimensional plane. If the shape is an arc and the central angle for forming the arc is θ (θ: warp angle), θ
The radial distribution of θ = (θt−θ ₀ ) × (R−R ₀ ).
/ (Rt−R ₀ ) + θ ₀ (θt: warp angle at blade tip, θ ₀ : R ₀ = warp angle at 0.35 Rt), θt = 25 ° to 35 °, θ ₀ = 32 ° to 42 °, θ
In the above developed view, t <θ ₀ , and the angle between the chord line of the blade and the straight line parallel to the rotation axis and passing through the leading edge of the blade is ξ
(Ξ: angle of deviation), the radial distribution of ξ is ξ = (ξt−ξ ₀ ) × (R−R ₀ ) / (Rt−R
₀ ) + ξ ₀ (ξt: wing angle at blade tip,
ξ ₀ : R ₀ = 0.35 Rt, and ξt = 58 ° to 68 °, ξ ₀ = 49 ° to 59 °, ξ
When t> ξ _0, and in the above developed view, where the chord length of the blade is L and the pitch at the same radial point between blades is T, the ratio T / L (T (T / L: string ratio) to T
An impeller of a blower, characterized in that /L=1.3 to 2.0.